This article is more than 5 years old. Information may no longer be current.
Subclinical AF increased stroke, silent cerebral infarct risk in diabetics
Subclinical atrial fibrillation is associated with a higher risk for stroke and silent cerebral infarct in patients with type 2 diabetes aged younger than 60 years, according to data in a new report.
“Silent brain infarcts should not be considered just intermediaries in the relationship between vascular risk factors and the risk for stroke but markets for other factors, such as brief episodes of AF, that lead to stroke,” Raffaele Marfella, MD, PhD, and colleagues wrote.
It is estimated that one-fourth of strokes are of unknown cause in patients with type 2 diabetes, according to background information in the study. Marfella and colleagues conducted the prospective, longitudinal, observational study to evaluate whether subclinical AF was a cause of stroke or other cerebrovascular diseases in younger patients with diabetes.
The researchers recruited 464 patients with type 2 diabetes (mean age, 52 years) from 2005 to 2009 and followed them for an average of 37 months. Inclusion criteria included age younger than 60 years and no documented arrhythmia disorders or stroke, among other conditions. Patients were matched with a control group of 240 healthy individuals without diabetes.
All patients were screened for subclinical AF using 48-hour ambulatory electrocardiographic Holter monitoring at 3, 6, 9 and 12 months after enrollment, and then once a year for the next 3 years. The researchers defined a brief subclinical episode of AF as AF duration <48 hours. All patients also received MRI of the brain to assess for silent cerebral infarct. Silent cerebral infarct was defined as low signal intensity area of 3 mm to 15 mm on T1-weighted images that could also be seen on T2-weighted images as a hyperintense lesion.
The prevalence of subclinical AF was greater for patients with diabetes compared with participants without diabetes (11.1% vs. 1.6%, P<.0001). During follow-up, 43 stroke events occurred in the patients with diabetes vs. 0 in the participants without diabetes. Those with diabetes who had episodes of subclinical AF (n=176) had a greater baseline prevalence of silent cerebral infarct (61% vs. 29%, P<.01) and more frequent occurrence of stroke events (17.3% vs. 5.9%, P <.01) compared with the other patients with diabetes (n=288).
Subclinical episodes of AF were shown to be independent determinants of silent cerebral infarct in patients with diabetes (OR=4.441; 95% CI, 2.42-8.16) and an independent predictor of whether a patient with diabetes would have a stroke (HR=4.6; 95% CI, 2.7-9.1).
“The risk of [silent cerebral infarct] was higher when subclinical episodes of AF were of longer duration, as evidenced by a positive correlation between AF burden and [silent cerebral infarct],” Marfella, of the department of geriatrics and metabolic diseases, Second University of Naples, in Naples, Italy, and colleagues wrote.
Disclosure: The researchers report no relevant financial disclosures.